1. Field of the Invention
The present invention relates to a display device. In particular, the present invention relates to a display device capable of displaying a three-dimensional (3D) image.
2. Description of the Related Art
Display devices are widely used, ranging from a large display device such as a television device to a small display device such as a mobile phone. High value-added products will be needed and are being developed. In recent years, display devices that can display 3D images have been developed in order to display more realistic images.
As methods for displaying a 3D image, there are a method using glasses for separating an image seen with a left eye and an image seen with a right eye (also referred to as an image separation method), and an autostereoscopic method by which a 3D image can be seen with the naked eye by addition of a structure for separating an image seen with a left eye and an image seen with a right eye in a display portion. It is not necessary to prepare glasses to perceive a 3D image when the autostereoscopic method is employed, which offers a high convenience. The 3D image display using the autostereoscopic method has been gradually spreading to a mobile phone, a mobile game console, and the like.
As a method for displaying a 3D image using the autostereoscopic method, there is known a parallax barrier method in which a parallax barrier is added to a display portion. A parallax barrier for this method is a stripe-shaped light-shielding portion and causes a decrease in resolution when display is switched from 3D display to two-dimensional (2D) display. In view of this, for a parallax barrier method, there is suggested a structure in which a liquid crystal panel having a patterned transparent electrode is used, and when display is switched between 2D display and 3D display, transmission or shielding of light by a liquid crystal layer is controlled by adjusting voltage applied to the transparent electrode in order that the presence or absence of a parallax barrier is set (see Patent Document 1).